Prometheus + JSON logging for grafana

[naps62]

Currently setting up a grafana dashboard on our hosted instace for some visualization

This sets up the app side of it to:

• output JSON logging (friendlier to grafana)
• expose a /metrics endpoint to the alloy scraper, which includes system metrics as well as some business ones (stack creation, etc)
• the metrics endpoint will be blocked from external access via traefik config

[vercel]

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Project	Deployment	Actions	Updated (UTC)
stacks	Ready	Preview, Comment	Feb 3, 2026 2:54pm

[Copilot]

Pull request overview

This PR adds Prometheus metrics and JSON logging support to enable Grafana dashboard visualization. The implementation includes structured logging with request context, a metrics endpoint for Prometheus scraping, and telemetry instrumentation for business events.

Changes:

• Added Prometheus metrics exporter with system metrics (VM memory, queue lengths) and business metrics (stack lifecycle, authentication events)
• Implemented JSON logging with LoggerJSON formatter and request metadata enrichment via LogMetadata plug
• Exposed /metrics endpoint for internal Prometheus scraping (secured via Docker network isolation)

Reviewed changes

Copilot reviewed 10 out of 11 changed files in this pull request and generated 15 comments.

Show a summary per file

File	Description
server/mix.exs	Added dependencies for telemetry_metrics_prometheus_core and logger_json
server/mix.lock	Updated lock file with new dependencies
server/lib/ethui_web/telemetry.ex	Configured Prometheus metrics reporter, converted metrics from summary to distribution with histograms, added business metrics definitions
server/lib/ethui_web/router.ex	Added /metrics endpoint in bare scope for Prometheus scraping
server/lib/ethui_web/endpoint.ex	Integrated LogMetadata plug into request pipeline
server/lib/ethui_web/plugs/log_metadata.ex	New plug to enrich logs with request context (request_id, user_id, stack_slug, etc.)
server/lib/ethui_web/controllers/metrics_controller.ex	New controller to expose Prometheus metrics via HTTP endpoint
server/lib/ethui_web/controllers/api/stack_controller.ex	Added telemetry events for stack creation and deletion
server/lib/ethui_web/controllers/api/auth_controller.ex	Added telemetry events for authentication code sending and verification
server/config/runtime.exs	Configured JSON logging for production environment
compose.saas.yml	Added Prometheus scraping labels for Docker service discovery

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